.file-box{
    display: inline-block;
    width: 120px;
    height: 120px;
    background-color: #dedede;
    border: 1px solid #cccccc;
    border-radius: 8px;
    cursor: pointer;
    overflow: hidden;
    position: relative;
}
.file-box > span{
    position: absolute;
    bottom: 0px;
    left: 0px;
    width: 100%;
    height: 20px;
    line-height: 20px;
    text-align: center;
    background-color: rgba(0, 0, 0, 0.6);
    color: white;
    font-size: 12px;
}
.file-box > input[type=file]{
    display: none;
}
.file-box > img{
    width: 100%;
    height: 100%;
    /* 等效于 background-size 的功能。主要是为img标签提供图片裁剪操作*/
    object-fit:scale-down;
    /* 等效于 background-position 的功能。主要是为img标签提供图片定位操作 */
    object-position: center;
}
.file-box > .loading{
    position: absolute;
    top: 0px;
    left: 0px;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
}
.loading > span{
    width: 100%;
    /* background-color: green; */
    height: 30px;
    position: absolute;
    top: 50%;
    left: 0px;
    transform: translate(0%,-50%);
    border: 1px solid white;
    box-sizing: border-box;
    font-size: 0px;
}
.loading i{
    display: inline-block;
    background-color: cornflowerblue;
    height: 100%;
}
